HEAT SINK

Abstract

A heat sink includes a first plate having a first surface with a heat source contact region, and a second surface has a looped peripheral groove, and first to n^th evaporation/condensation grooved sections arranged sequentially within the looped peripheral groove. Each grooved section has parallel grooves. The first grooved section is disposed in an area corresponding to the contact region, and each groove therein has a leading end connected to the looped peripheral groove. Every two grooves in each of the second to n^th grooved sections have leading ends connected to a trailing end of one groove in the preceding grooved section. The grooves in the n^th grooved section having trailing ends connected to the looped peripheral groove.

Description

CROSS REFERENCE TO RELATED APPLICATION

[0001] This application claims priority of Taiwanese Application No. 099147428 filed on Dec. 31, 2010.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to a heat sink and, more particularly, to a heat sink having a high heat dissipating efficiency.

[0004] 2. Description of the Related Art

[0005] Electronic and electrical products generate heat when they are operated. Basically, such heat will affect the operating performance of the electronic and electrical products. Therefore, to quickly and effectively dissipate such heat is of a great concern in the art.

[0006] A conventional heat sink generally includes a heat conducting member disposed on a heat-generating source to heat exchange with the heat-generating source, and a plurality of heat dissipating fins that extends upwardly from the heat conducting member for dissipating the heat absorbed by the heat conducting member. However, such a heat sink has a problem that the heat accumulated between the heat-dissipating fins may be unable to be dissipated resulting in poor heat dissipating efficiency.

SUMMARY OF THE INVENTION

[0007] Therefore, an object of the present invention is to provide a heat sink that has a high heat dissipating efficiency.

[0008] According to an aspect of the present invention, there is provided a heat sink which comprises a first plate including a first surface that has a contact region adapted to contact a heat source, and a second surface opposite to the first surface and having an area corresponding to the contact region. The second surface includes a looped peripheral groove that extends along a periphery of the first plate, and first to n^th evaporation/condensation grooved sections that are arranged sequentially from the area of the second surface to another area away from the area. Each of the first to n^th evaporation/condensation grooved sections has m number of substantially parallel grooves extending in a direction from the area to another area of the second surface. Each of the grooves of the first evaporation/condensation grooved section is disposed in the area and has a leading end connected fluidly to the looped peripheral groove. The number of the grooves in each succeeding one of the second to n^th evaporation/condensation grooved sections is twice the number of the grooves in a preceding one of the second to n^th evaporation/condensation grooved sections. Every two of the grooves in each succeeding one of the second to n^th evaporation/condensation grooved sections has leading ends connected to a trailing end of one of the grooves in the preceding one of the second to n^th evaporation/condensation grooved sections. The grooves in the n^th evaporation/condensation grooved section have trailing ends connected fluidly to the looped peripheral groove. A second plate is bonded sealedly to the second surface of the first plate to close the grooves in the first to n^th evaporation/condensation grooved sections and the looped peripheral groove.

[0009] According to another aspect of the present invention, there is provided a heat sink which comprises: a coolant housing adapted to contact a heat source and having a receiving space to contains a coolant; a first fin unit disposed in the receiving space and having a hollow central body and a plurality of fins projecting radially from the hollow central body; a heat conducting member having one end portion inserted axially into the hollow central body and another end portion extending out of the coolant housing; and a second fin unit having a hollow central body disposed around the another end portion of the heat conducting member, and a plurality of fins projecting radially from the hollow central body of the second fin unit.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiments with reference to the accompanying drawings, of which:

[0011] FIG. 1 is a schematic plan view of a first plate of a heat sink of a first preferred embodiment according to the present invention;

[0012] FIG. 2 is a schematic side view of a second plate of the heat sink of the first preferred embodiment according to the present invention;

[0013] FIG. 3 is a schematic perspective view of the heat sink of the first preferred embodiment in an assembled state;

[0014] FIG. 4 is a is a schematic side plan view to illustrate a modification of the second plate of the heat sink of the first preferred embodiment according to the present invention;

[0015] FIG. 5 is a schematic top plan view of a heat sink of a second preferred embodiment according to the present invention;

[0016] FIG. 6 is a schematic sectional view of the heat sink according to the second preferred embodiment of the present invention;

[0017] FIG. 7 is a schematic plan view of a first plate of a heat sink according to a third preferred embodiment of the present invention;

[0018] FIG. 8 is a schematic sectional view taken along line VIII-VIII in FIG. 7;

[0019] FIG. 9 is a schematic plan view to illustrate a modification of a heat conducting member of the heat sink of the third preferred embodiment;

[0020] FIG. 10 is a schematic sectional view taken along line X-X in FIG. 9;

[0021] FIG. 11 is a schematic plan view to illustrate another modification of the heat conducting member of the heat sink of the third preferred embodiment;

[0022] FIG. 12 is a schematic sectional view taken along the line XII-XII in FIG. 11;

[0023] FIG. 13 is a schematic plan view of a first plate of a heat sink of a fourth preferred embodiment according to the present invention;

[0024] FIG. 14 is a schematic plan view of a first plate of a heat sink of a fifth preferred embodiment according to the present invention; and

[0025] FIG. 15 is a schematic sectional view taken along line XV-XV in FIG. 14.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] Before the present invention is described in greater detail, it should be noted that like components are assigned the same reference numerals throughout the following disclosure.

[0027] FIGS. 1, 2 and 3 are schematic views for illustrating a heat sink of a first preferred embodiment according to the present invention.

[0028] Referring to FIGS. 1, 2 and 3, the heat sink of the first preferred embodiment of the present invention generally comprises a first plate 1 (shown in FIGS. 1 and 3) and a second plate 2 (shown in FIGS. 2 and 3).

[0029] The first plate 1 includes a first surface 10 that has a contact region 100 (a region encircled by dotted lines in FIG. 1) near one end thereof, which is adapted to contact a heat source, and a second surface 11 opposite to the first surface 10 and having an area corresponding to the contact region 100. When in use, the heat sink is arranged in such a manner that the contact region 100 is in contact with the heat source (not shown).

[0030] The second surface 11 of the first plate 1 includes a looped peripheral groove 110 that extends along a periphery of the second surface 11 of the first plate 1, and first to n^th evaporation/condensation grooved sections 111₁ to 111_n that are arranged sequentially from the area corresponding to the contact region 100 to another area away from the area.

[0031] The second surface 11 of the first plate 1 includes first to fifth evaporation/condensation grooved sections 111₁ to 111₅ in this embodiment. A section of the looped peripheral groove 110 that passes through the contact region 100 is a liquid collection region 1100.

[0032] The liquid collection region 1100 is filled with a coolant. The coolant may be water, an aqueous hexane solution, or any other suitable liquid that can be converted from a liquid state to a gas state at a predetermined temperature.

[0033] More specifically, in this embodiment, the first evaporation/condensation grooved section 111₁ is disposed in an area adjacent to the liquid collection region 1100 of the looped peripheral groove 110 and has four substantially parallel grooves 111A extending in a direction away from the liquid collection region 1100. Each of the grooves 111A of the first evaporation/condensation grooved section 111₁ has a leading end extending to and connected fluidly to the liquid collection region 1100 of the looped peripheral groove 110.

[0034] The second evaporation/condensation grooved section 111₂ has eight substantially parallel grooves 111B extending away from the first evaporation/condensation grooved section 111₁. Every two of the grooves 111B in the second evaporation/condensation grooved sections 111₂ have leading ends extending to a trailing end of a respective one of the grooves 111A so as to be connected fluidly to the same.

[0035] The third evaporation/condensation grooved section 111₃ has sixteen substantially parallel grooves 111C extending away from the second evaporation/condensation grooved section 111₂. Every two of the grooves 111C in the third evaporation/condensation grooved sections 111₃ have leading ends extending to a trailing end of a corresponding one of the grooves 111B so as to be connected fluidly to the corresponding groove 111B.

[0036] The fourth evaporation/condensation grooved section 111₄ has thirty-two substantially parallel grooves 111D extending away from the third evaporation/condensation grooved section 111₃. Every two of the grooves 111D in the fourth evaporation/condensation grooved sections 111₄ have leading ends connected to a trailing end of a corresponding one of the grooves 111C so as to be connected fluidly to the corresponding groove 111C.

[0037] The fifth evaporation/condensation grooved section 111₅ has sixty-four substantially parallel grooves 111E extending away from the fourth evaporation/condensation grooved section 111₄. Every two of the grooves 111E in the fifth evaporation/condensation grooved sections 111₅ have leading ends connected to a trailing end of a corresponding one of the grooves 111D so as to be connected fluidly to the corresponding groove 111D. The grooves 111E in the fifth evaporation/condensation grooved section 111₅ have trailing ends connected fluidly to the looped peripheral groove 110.

[0038] The second plate 2 is bonded sealedly to the second surface 11 of the first plate 1 to close the grooves 111A, 111B, 111C, 111D, and 111E in the first to fifth evaporation/condensation grooved sections 111₁ to 111₅ and the looped peripheral groove 110 so that the looped peripheral groove 110 of the first plate 1 and the grooves 111A, 111B, 111C, 111D, and 111E are all in a vacuum state.

[0039] By virtue of the abovementioned structure, when the heat sink is disposed so that the contact region 100 is in contact with the heat source (not shown), heat is transferred from the heat source to the liquid collection region 1100 of the looped peripheral groove 110 in the first plate 1 through the contact region 100 and is absorbed by the coolant in the liquid collection region 1100. The temperature of the coolant is increased due to the absorbed heat. When the temperature of the coolant reaches the boiling point thereof, the coolant is converted into a gas state, and passes sequentially through the first to fifth evaporation/condensation grooved sections 111₁ to 111₅. The vaporized coolant is condensed because of its contact with the surfaces of the grooves 111A, 111B, 111C, 111D, and 111E when it passes through the first to fifth evaporation/condensation grooved sections 111₁ to 111₅. After passing through the grooves 111E, the vaporized coolant condenses flowing to the looped peripheral groove 110. Thereafter, the condensing coolant returns to the liquid collection region 1100 to continue a next cooling cycle.

[0040] Referring to FIG. 4, the second plate 2 has a surface opposite to the first plate 1 and formed with a plurality of fins 20. Each of the fins 20 has a root proximate to the surface of the second plate 2, and an end portion distal from the root. Preferably, the root is larger in thickness than the end portion.

[0041] The heat sink of the present invention may be applied to any one of devices that can generate heat during their operations, such as light emitting diode (LED) light source modules, dynamic random access memory (DRAM) modules, street lamps, and air conditioners.

[0042] Referring to FIGS. 5 and 6, the heat sink of the second preferred embodiment comprises a coolant housing 30, a first fin unit 31, a heat conducting member 32, and a second fin unit 33.

[0043] The coolant housing 30 is adapted to contact a heat source (not shown) and has a receiving space 300 to contain a coolant. Similar to the first preferred embodiment, the coolant in this embodiment may be water, an aqueous hexane solution, or any other suitable liquid that can be converted from a liquid state to a gas state at a predetermined temperature.

[0044] In this embodiment, the first fin unit 31 is disposed in the receiving space 300 and has a generally cylindrical hollow central body 310 and a plurality of fins 311 projecting radially from the hollow central body 310. Each of the fins 311 has a root proximate to the surface of the hollow central body 310, and an end portion distal from the root. Preferably, the root is larger in thickness than the end portion.

[0045] The heat conducting member 32 has one end portion inserted axially into the hollow central body 310 of the first fin unit 31 so that the heat conducting member 32 can be heat exchanged with the hollow central body 310 of the first fin unit 31. Another end portion of the heat conducting member 32 extends out of the coolant housing 30.

[0046] The second fin unit 33 basically has the same structure as the first fin unit 31. Similar to the first fin unit 31, the second fin unit 33 has a generally cylindrical hollow central body 330 disposed around the another end portion of the heat conducting member 32, and a plurality of fins 331 projecting radially from the hollow central body 330 of the second fin unit 33. Similar to the hollow central body 310 of the first fin unit 31, each of the fins 331 has a root proximate to the surface of the hollow central body 330, and an end portion distal from the root. Preferably, the root is larger in thickness than the end portion. The another end portion of the heat conducting member 32 is inserted axially into the hollow central body 330 of the second fin unit 33 so that the heat conducting member 32 can be heat exchanged with the hollow central body 330 of the second fin unit 33.

[0047] When the heat sink of the second preferred embodiment is disposed on a heat source (not shown), heat may be absorbed by the coolant contained in the coolant housing 30 and the first fin unit 31. Next, the heat conducting member 32 is heat exchanged with the first fin unit 31 so that the first fin unit 31 and the coolant can be cooled quickly. Finally, the heat conducting member 32 is heat exchanged with the second fin unit 33. Therefore, the heat is conducted smoothly out of the coolant housing 30, and the temperature of the heat source can be maintained stably within a desirable range.

[0048] FIGS. 7 and 8 are schematic views of the third preferred embodiment of the present invention. As shown in FIGS. 7 and 8, this embodiment is different from the first embodiment in that the heat sink further comprises two heat conducting members 112 inserted in the looped peripheral groove 110. By virtue of the heat conducting members 112, the returned coolant can be further cooled. This is beneficial to the next cooling cycle. It is noted that the two heat conducting members 112 shown in FIGS. 7 and 8 may be replaced with a single heat conducting member 113 shown in FIGS. 9 and 10. On the other hand, the heat conducting member 113 shown in FIGS. 9 and 10 may be replaced with a heat conducting member 114 shown in FIGS. 11 and 12.

[0049] FIG. 13 illustrates a fourth preferred embodiment of the present invention. This embodiment is different from the first embodiment in that two looped peripheral grooves 110' are formed on the second surface 11 of the first plate 1, and a common a liquid collection region 1100' formed between the looped peripheral grooves 110'. An area on the first surface 10 of the first plate 1 that corresponds to the liquid collection region 1100' is a contact region (not shown) to contact a heat source. Each looped peripheral groove 110' is connected to the evaporation/condensation grooved sections 111₁ to 111₃.

[0050] FIGS. 14 and 15 are schematic views of a fifth preferred embodiment of the present invention. This embodiment is different from the fourth embodiment in that two heat conducting members 115 are inserted into each looped peripheral groove 110'.

[0051] While the present invention has been described in connection with what are considered the most practical and preferred embodiments, it is understood that this invention is not limited to the disclosed embodiments but is intended to cover various arrangements included within the spirit and scope of the broadest interpretation so as to encompass all such modifications and equivalent arrangements.

Claims

1. A heat sink comprising: a first plate including a first surface that has a contact region adapted to contact a heat source, and a second surface opposite to said first surface and having an area corresponding to said contact region, said second surface including a looped peripheral groove that extends along a periphery of said first plate, and first to n^th evaporation/condensation grooved sections that are arranged sequentially from said area of said second surface to another area away from said area, each of said first to n^th evaporation/condensation grooved sections having m number of substantially parallel grooves extending in a direction from said area to said another area of said second surface, each of said grooves of said first evaporation/condensation grooved section being disposed in said area and having a leading end connected fluidly to said looped peripheral groove, the number of said grooves in each succeeding one of said second to n^th evaporation/condensation grooved sections being twice the number of said grooves in a preceding one of said second to n^th evaporation/condensation grooved sections, every two of said grooves in each succeeding one of said second to n^th evaporation/condensation grooved sections having leading ends connected to a trailing end of one of said grooves in the preceding one of said second to n^th evaporation/condensation grooved sections, said grooves in said n^th evaporation/condensation grooved section having trailing ends connected fluidly to said looped peripheral groove; and a second plate bonded sealedly to said second surface of said first plate to close said grooves in said first to n^th evaporation/condensation grooved sections and said looped peripheral groove.

2. The heat sink of claim 1, wherein said second plate has a surface opposite to said first plate and formed with a plurality of fins.

3. The heat sink of claim 2, wherein each of said fins has a root proximate to said surface of said second plate, and an end portion distal from said root, said root being larger in thickness than said end portion.

4. The heat sink of claim 1, further comprising at least one heat conducting member inserted into said looped peripheral groove.

5. A heat sink comprising: a coolant housing adapted to contact a heat source and having a receiving space to contain a coolant; a first fin unit disposed in said receiving space and having a hollow central body and a plurality of fins projecting radially from said hollow central body; a heat conducting member having one end portion inserted axially into said hollow central body and another end portion extending out of said coolant housing; and a second fin unit having a hollow central body disposed around said another end portion of said heat conducting member, and a plurality of fins projecting radially from said hollow central body of said second fin unit.

6. The heat sink of claim 5, wherein each of said fins of at least one of said first and second fin units has a root proximate to said hollow central body of the respective one of said first and second fin units, and an end portion distal from said root, said root being larger in thickness than said end portion.